Evolutionary Biography

(Space, time, form: the biological synthesis)

This web page presents aspects and applications of the biogeographic method and synthesis known as panbiogeography first developed by Leon Croizat (1894-1982). Panbiogeography provides a cartographic method for analyzing the geographic (spatial) structure of distributions to generate predictions about the origin of species and other taxa in space and time.

Panbiogeography links
Panbiogeographic Method   Biogeography and the Galapagos   Leon Croizat Biography   Before Croizat et al 1974   Articles from Tuatara 27 (1) (1984)   Jardín Botánico Xerófito "Dr. León Croizat"   Space, Time, Form - articles by Croizat   Panbiogeographic Publications   Bibliography - early classics   Biogeograpfia   Biological Evolution   Video documentaries on Croizat   Panbiogeography Gate	Leon Croizat during the 1950-1951 Franco-Venezuelan Expedition to the sources of the Orinoco River

Panbiogeography is: An attempt to reintroduce and reemphasize the importance of the spatial or geographic dimension of life's diversity for our understanding of evolutionary patterns. An approach to biology that focuses on the role of locality and place in the history of life. Research goal: To recover the importance of places and localities as direct subjects of analysis in biogeography. Core position: The acknowledgement that an understanding of locality is a fundamental precondition to any adequate analysis of the patterns and processes of evolutionary change. Research emphasis: The role of place in the process of the past as understood from the perspective of the present.

Comemorative medalion in honor of Leon Croizat at the XXVIII meeting of the Congresso della Societá di Biogegrafia, Italy (Zunino, 1992).

Assumptions of the panbiogeographic method

1. Distribution patterns constitute and empirical database for biogeographical analysis.
2. Distribution patterns provide information about where, when, and how animals and plants evolve.
3. The spatial and temporal component of these distribution patterns can be graphically represented.
4. Testable hypotheses about historical relationships between the evolution of distributions and earth history can be derived from geographical correlations between distribution
   graphs and geological/geomorphic features. 

"Earth and life evolve together"

The evolutionary implication of Croizat's panbiogeography is a much closer evolutionary relationship between organisms and their environment than supported by Darwinian biogeography where dispersal abililty is portrayed as a function of the organism (the different 'means of dispersal').

The above cartoon exemplifies the concept of biological distribution being constrained by factors that are inherent in neither the organism or environment alone, but organism/environment boundaries specific to particular places, times, and organisms. Here the boundaries are represented metaphorically in the form of an organism/environment fence. Illustration prepared by Frank Climo, Wellington, New Zealand.

Page from one of the numerous notebooks on biogeography and biology maintained by Croizat while at the Arnold Arboretum. These booklets were to provide a major source of information while Croizat wrote his books and articles in Venezuela 

Historical background

Leon Croizat emigrated from Italy to the United States in 1924, and during the 1930's he met E. D. Merrill who became Director of the Arnold Arboretum in 1936. Merrill provided Croizat with the position of technical assistant, but when Merrill was forced out of office ten years later, Croizat was also dismissed, apparently in retaliation for publishing an article critical of work by Irwin Bailey of the Arboretum (Craw, 1984). Croizat subsequently accepted an academic position with the Universidad Central de Venezuela and in the following years he continued to write on botany and biogeography with the support of his wife Catalina, a child psychologist and later a landscape architect. Together they developed a major botanical garden of xerophytic plants outside the town of Coro (Craw 1984; Grehan, 1990a; Zunino, 1992). Croizat's formal training was in law, for which he received a doctorate (Zunino, 1992), but he had a long-standing interest in biology and botany. He was later to refer to his training in law as a critical foundation for presenting evidence in support of his biogeographic and botanical arguments.

Croizat wrote prolifically on biogeography. His first book, published by Junk in 1952, presented the first comprehensive global review of spatial congruence for plant and animal distributions. It now sells for about $150 in the used book market.	Croizat's second major publication was privately published in 1958 in Caracas, Venezuela. This became a choice of necessity to avoid the editorial censorship that would otherwise have prevented publication.